Recent technology regarding disk drive is making a rapid advance in linear track recording density due to improvements of the head devices. Along with this, a much finer track pitch is required for a larger recording density in normal direction to the tracks. A mechanism capable of driving the head with a finer scale is needed to follow the narrow track width precisely with a magnetic head.
Now, a hard magnetic disk drive is described, which has a larger storage capacity due to improved recording density among other disk drives, and has an enlarged application fields other than personal computers (PC). FIG. 21 shows a plan view of head suspension assembly 200 used in a typical hard magnetic disk drive. In FIG. 21, slider 102 having a magnetic head for recording data to or reproducing data from rotating magnetic disk 150 is mounted on distal end of load beam 104 (or suspension arm). Another end of load beam 104 is mounted to carriage 106 pivotally around projection 108 as a center of rotation within minute angles. Carriage (or actuator arm) 106 is pivotally mounted to shaft 110 fixed on a housing (not shown) of hard magnetic disk drive.
Voice coil 114, a part of magnetic circuit 112, is firmly mounted on the housing. Upon applying exciting current to voice coil 114, a magnetic force generated against a permanent magnet (not shown) mounted on carriage 106 moves carriage 106 pivotally. Carriage 106 moves pivotally relative to a controlled exciting current to voice coil 114 to transport slider 102 equipped with a head radially to a target location on a disk.
A pair of piezoelectric elements 116 are provided between carriage 106 (or actuator arm) and load beam 104 (or suspension arm). The piezoelectric elements 116 are disposed on carriage 106 symmetrically each other at a small amount of angles longitudinally as shown in FIG. 21.
Extension and contraction movements exerted by respective actuator elements 116, indicated by arrows A14 in FIG. 21, can displace slider 102 mounted at the distal end of load beam 104 slightly to position on the target location of the surface of magnetic disk 150 precisely.
In aforementioned head suspension assembly 200, piezoelectric elements 116 are placed between members provided on load beam 104 and carriage 106 respectively, and are pressed to touch load beam 104 and carriage 106 respectively in their side surfaces. Consequently, extension and contraction movement exerted by respective actuator elements 116 moves load beam pivotally to give slider 102 a slight displacement.
However, in a typical head suspension assembly as shown in FIG. 21, the problem is that respective actuator elements must be mounted individually, which not only needs additional assembling processes but not free from risks of breakage for piezoelectric elements in the assembling processes.